The application claims the benefit of a priority under 35 USC 119 to French Patent Application No. 01 08899 filed Jul. 4, 2001, the entire contents of which are hereby incorporated by reference.
The present invention relates to a device for attaching structural elements and, in particular, a first structural element to a second structural element. In particular, the present invention relates to device for attaching a cover or similar element to a structural element. In particular, the present invention is directed to a quarter-turn device. The device has practical application in many fields of technology and especially in the field of medical equipment.
Quarter-turn attachment devices are well known. These devices generally comprise an attachment element passing through a hole in the cover and a retaining element placed on the structural element. The attachment element generally comprises a shank having at one end a head and at the other end a part which is profiled so that it can be engaged in, and withdrawn from the retaining element, generally along the axis of the shank, in a first angular position of the attachment element, and so that it can be retained in the retaining element in a second angular position offset by 90xc2x0 with respect to the first angular position. In general, the heads has a circular shape with a working recess in the form of a diametrical slot in the upper face of the head.
These attachment devices are commonly used in numerous applications. However, there are certain fields of applications, such as, in the field of medical equipment, and more particularly, radiology equipment, in which there are particular problems. These particular problems include, for example, hygiene, ease of cleaning and safety (the impossibility or at least the difficulty of application by unskilled persons). As a consequence, the known quarter-turn devices are not entirely satisfactory.
An embodiment of the present invention is a quarter-turn attachment device, which addresses the problems of, for example, hygiene, ease of cleaning and safety.
The quarter-turn device for attaching a cover or a similar element to a structural element comprises an attachment element passing through a hole in the cover and a retaining element arranged on the structural element. The attachment element comprises a shank having an axis and comprising at one end a head and at the other end a part that is profiled so that it can be engaged in, and withdrawn from, the retaining element, generally along the axis of the shank, in a first angular position of the attachment element. Further, the device can be retained in the retaining element in a second angular position offset by 90xc2x0 with respect to the first angular position. The head may have a periphery, generally circular shape, with an upper face and with a recess in the form of a diametrical slot in the upper face. The slot has a generally longitudinal profile with a curved bottom in the shape of a circular arc, the center of which is located at some distance above the head, such that the two opposed longitudinal ends of the slot open out from the upper face of the head at two points offset radially inwards with respect to the circumference of the head.
In an embodiment, the upper face of the head is curved in a convex manner with a radius of curvature, which may be substantially equal to the diameter of the head.
In an embodiment, the slot has a transverse profile with a bottom curved in a concave manner.
In an embodiment, the width of the slot is at least equal to and greater than the maximum depth of the slot at the center of the head.
In an embodiment, the radius of curvature of the circular-arc-shaped bottom of the longitudinal profile of the slot may be substantially equal to the diameter of the head.
In an embodiment, the attachment element may be fitted with a sealing element, which is placed between the lower face of the head and the cover to be attached. The sealing element may have an outer diameter greater than the diameter of the head.
In an embodiment, the sealing element in the form of an annular seal has an outer peripheral edge profiled such that the edge of the seal provides continuity substantially without a shoulder between the head and the cover.
In an embodiment, the cover to be attached may be fitted, in the region of the hole designed for the attachment element to pass through, with a cavity having a diameter and a depth such that the head of the attachment element and the sealing element inserted between the head and the cover substantially fill the cavity.
In an embodiment, the attachment device comprises a special tool for applying the attachment element. This tool comprises a flat part in the shape of a sector of a disc having a radius of curvature corresponding to the radius of curvature of the bottom of the longitudinal profile of the slot of the head of the attachment element and a peripheral transverse profile corresponding to the bottom of the transverse profile of the slot.